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Easy Retopologising models preserving the fine-detail levels (by Rastaman)

Easy Retopologising models preserving the fine-detail levels

Why should you retopologise your models ?

There are several reasons why you should think about ‘retopoing’ your existing models.

Maybe you already have created a very good model, but some areas doesn’t render cleanly because of a bad topology there. Simply retopo your model and fix the bad areas.

On the other hand, the availability of the retopology-feature gives you less stress when you sculpt your models.

Just follow your imagination, create how you like without always having the flow of your polygon-connection-lines in mind.
When you’re happy with the shape you created, simply reotopo the model and you will have a clean mesh.

So far, so good.
But as simple as it sounds, you will soon discover that it is by far not so easy.

The major problem beside the handwork is that you will loose the details of the original mesh.

But the soulution for that is already described in the Wiki under the topic:

‘1.3 Importing Topology From Outside of ZBrush’

But I must say, I did read it but I simply did not realize a long time what it really meant.

So I decided to make this short tutorial to give a clear step-by step how to use this principle with retopoed meshes.

[attach=63917]Retopo_detail-Topostatus_big.jpg[/attach]

I had to open a new thread because I cannot edit my main topoplogy-thread any more.

Important:
Watch also page 2 of this thread for a short description of how to merge different high-detailed-meshes with this technique.:wink:

Enjoy. :smiley:

Attachments

Retopo_detail-Topostatus_big.jpg

Retopo_detail-Topostatus_big.jpg

:smiley: Wow man I seriously have learned more from you than the actual “guides” thank u for sharing I really learn.

Rastaman! Thanks for making and sharing the tutorial. I was wondering how you would do such a thing. I’m going to give it a go on a model that I have preped…wish me luck!

Again, thank you very much for posting this up, I know it was a lot of hard work!

Peace,

NickZ. :slight_smile:

Rastaman,

Ok so I have followed all of the steps but I am running into a scale issue. Perhaps you could tell me what I have screwed up.

  1. So I have my original model (Hi res detail) loaded.

  2. I have my retoplogized mesh )Lo res mesh) loaded.

  3. Draw the zphere.

  4. Go into the rigging section and use “select mesh” and select my Hi Res Mesh.

  5. Go into the Topology section and use the “select Topo” and select my Lo Res mesh. (resurfaced mesh)

Everything loads but I have a problem.

alienHost_retop_problem.jpg

The scale of my resurfaced mesh (Lo Res mesh) is off for some reason. I have checked the scale as a sub tool and everything lines up just fine. I have even checked the scale as a sub tool and then saved that out as a .ZTL file and used that mesh, but the results are the same.

Wondering if you have run into this or not.

Thanks,

NickZ. :slight_smile:

@ Nickz:

I have just rechecked my setup with the demo-head from my tutorial, it works without scale problems.

I only had this scale thing when I exported the retopoed low-poly as an object and imported it again.
With saving it directly as a .ztl the scale issue didn’t appear again.

Try this:

  1. Be sure that you have turned off any transpose translation/scaling - line.
    Therefore go within your original model into move,scale or rotate-mode and LMB-Click once on any point of your mesh.
    The transpose-line should now disappear.
    Now do your retopo-work.
    When you created the retopoed low-polymesh, check this again for that mesh before you store it as .ztl or export it as an object.

If this does not solve your problem, try this:

  1. Use the retopoed low-poly-mesh directly without first saving and reloading it.
    If any transpose line is turned off before you do any retopo-work, you should have exactly the same scaling between the original-mesh and the low-poly-retopo-mesh.

One note @ All:

I just checked my created final mesh with the transfered details closer and found some wired connection-lines running from the internal-mesh-surface to the point where the basic zsphere was located. (the one you choosed from the tool-palette in the detail-transfer-setup).
If that occurs in your attempts, try to watch out for any connections between the topology and the base-zsphere when you setup your fine-detail-transfer and try to delete that connections before you make the final adaptive skin.

One further note for all who think about that possibility:
(I already posted this in Plakkies Thread)

In the Wiki, under the topic polypainting and remapping UV’s within the polypaint-process, a method is described for reimporting UV-Sets via an saved low-poly version of your model. (we also use this technique now for posing with topo-rigs for transfering the high detailed structure onto a posed low-poly version of the model.)

If you save a low-poly version of your retopoed work and reimport it later (after polypainting or posing with topo-rigs) when your high-poly-model in ZBrush is in exactly the same subd-level as your .obj with the new UV-Set, the imported .obj will replace the originial mesh as well as the UV’s (equal if they existed before on your high-poly mesh or not). Structure and UV’s will be replaced by the imported .obj-version, but all paintings and subd-levels are still there.

In my work for my new topo-tutorial (see my post above) I tried this technique also for transfering the fine-details from the high-poly-mesh (with bad topology) to the retopoed low-poly-mesh.
For two reasons this does not work with the .obj-Reimport-trick:

First the reimport of an .obj into an active mesh is only allowed when they are in exactly the same subd-level and have exactly the same number of poly-surfaces and poly-points.
Otherwise you will get an error message…:confused:

Fine, I thought, let’s alter the retopoed lowpoly-mesh a little bit to match the number of surfaces and points just like the original mesh by inserting or deleting some points / surfaces on not crucial (means hidden) parts of the model.:cool:
Well, you can do so and ZBrush will begin to reimport the tweaked .obj, but it also crashes after some seconds.

So this technique does not work for transfering details within mesh-versions that have changed in the basic structure.:td:

Rasta, I already posted in the Lab, but I’ll do it here as well. This looks brilliant. This could be the thing that would help me big time with my model. I already tried a total retopo to merge head and neck, but lost some detail. I’ll spend the night testing and show you the results.
Many many many many thanks!!!
Plakkie

He,he, go for it, Plakkie.:+1:

I am not sure if you can succeed with that in the merging-process because when you made the ‘Make Polymesh 3D’s’ for the mesh-insert-step, you have already lost your subd-levels.
But maybe you can tweak this step to get the two parts with accessable subd-levels together, then you can use my descriped way.

If the ‘Reconstruct-Sudiv’ - function would work properly, all problems would be solved in a minute.:roll_eyes:

You would Make Polymesh3D both parts in their highest subd-levels, make the insert-mesh step and then Reconstruct the lower subd-levels for the new roughly connected mesh.

Then doing the retopo-work and detail-transfer-setup as described, we should mostly come to suitable results.

Rastaman,

Thanks again bud! This is great! I got it to work. I had to use the “make polymesh 3D” (In the Tool palette) on the resurfaced mesh that had the correct scale. I then saved that as a .ZTL and then used the Load Tool to bring it back intoZB. Now my model had the correct scale and I could go about using the retopology detail projection method that you outlined.

Here is the results:

[attach=63945]alienHost_retop_final.jpg[/attach]

I hope this gets highlighted somehow because this is a HUGE workflow improvement. Now you can sculpt as a concept, not worry about topology, retopologize, capture that detail and then start to go to town on the final mesh.

Oh this is so cool…I feel like a ZB fan boy now.

Thanks again,

NickZ.

Attachments

alienHost_retop_final.jpg

Nickz,

glad that it works for you now and thanks for the hint which is very usefull to know.
I will include it in the tutorial soon.

And very nice model, :+1:

Nickz’s and my remarks to the scale-problem are now included in the tutorial.:+1:

Did you talk about the ability to store a morp target before you project your detial? I did this and was able to “paint” out any areas of my model that ddin’t project well.

Thanks again!

NickZ. :slight_smile:

P.S. Thanks for the props on my model! :slight_smile:

Yes, I have this topic already in my tutorial, but one phrase at the end is missing (think I kicked it out by accident) that the morph-target can be used for revealing the details that doesn’t come up with the main detail-transfer-process.

I’ll fix this immediately. thanks again for the hint.:+1:

You can use the usual sliders or the new Morph-target-brush-workflow for that. (see Wiki)

I just updated the tutorial with an appendix-section of how to use the Morph-Brush to reveal all missing details.:smiley:
If Nickz ore someone else has further tips, please let me know.:wink:

@ Nickz: You’re wellcome.

I like the solution of your retopo-work in how you came around with a good Topo-flow at the nose (without ending in a single point) for the front-face-section. Very clever.:+1:
I only think you will have some problems if you plan to animate the mouth.:wink:

Well, I gave it my best… but I haven’t got the results I wished. Here’s a large picture to show what I mean. First the original:

[original.jpg](javascript:zb_insimg(‘63962’,‘Rastaretopo.jpg’,1,0))

I can only correct those artefacts by using smooth brush and elinating the fine lines and details I’ve worked on so hard. :frowning:
It’s quite demotivating. I love to continue on this model, but I can’t without knowing if I can connect the different parts together without loosing so much work and effort.

All in all thanks Rasta for thinking out yet another option. Do you think there’s a way to get cleaner detail out of my original mesh into a retopo-one?

Attachments

Rastaretopo.jpg

Try going over it with the Clay Brush, see what that makes it look like. Good luck!

Nope, the clay brush won’t solve the blocky artefacts without seriously altering the geometry.

Maybe I have a solution.:confused:

Wait a little bit, I’ll check it soon.

Retop it then go over it with a morph brush? That might do it.

Plakkie, I have your solution. just wait some minutes, I will give you a detailed step-by step.:wink: